OK I have been reading about the New LS OIL with the zinc additive. Is that better than the 5W30 AMSOIL I just bought and do our cars need the zinc????
Opinions appreciated!!!

 

Are talking about the Joe Gibbs oil? Not legal for street use because it has all that zinc in it.

 

Which statute or DOT regulation limits zinc levels in engine oil, exactly?

The only actual risk is your engine warranty, if it has one. GM's Dexos spec oil may be required in order to preserve the engine warranty, and no way does Gibbs LS oil carry Dexos certification.

 

the short answer is this.

zinc and phosphorus were removed from conventional oils because if burned up catylitic converters.

engines need it ,as it acts as a lubricant for high performance engines as they all have tremendous pressures on bearings and such.

oils without the star on the label still have the two additives as do oils with weights of 10W40 and above.

sythetic solved the problem just fine, mobil 1 is one of the best out there. it became a real problem in motorcycles, i started running delo 400 as it was designed for a deisel and they have no converters, so the oil has all the additives, and worked good in my bikes. i now run shell rottella full synthetic and it rocks.

if your engine was designed to run well on 5W30 run any of the synthetics, if you change it every 3,000 miles it makes very little difference how high the quality, it ain't in there long enough to matter.

chevy reccomends mobile 1 5W 30 in my 2012 LS3 so what the heck, i'll play along. the big thing to me is a good quality filter, i use nothing but K&N oil filters at about 5 bucks a copy, i pretty much ignore the percentage meter on the vette and change the oil about every 3 to 5K depending on the driving conditions.

don't listen to all the racing hype. i was a NASCAR driver at one time. my crew chief used kendall 50 wt. in motors that cost thousands of sponser dollars and i never blew one up.

the manufacturer spends a boatload of money on engineers that know pretty much what the motors need. i don't pretend to know more than them, and don't 2cd guess them much.

 

Cars that see the track, high temps and hard driving can do well to utilize synthetic oils with higher zinc/phosphorous for wear protection. No one gives a **** about catalytic converters when a $12-15,000 engine is on the line; not to mention when we're worried about catalytic converter lifespan, remember that your M1 5w30 has around 750ppm of zinc/phos and the preferred oils carry slightly less than half that - or around 1200 ppm. Unless you're burning a quart of oil every few thousand miles (you're not), the loss of converter lifespan is probably negligible for most drivers: whoopee.

10 weight oils are exempt from the EPA regs, so Mobile One 10w40 for example has higher ZDDP concentrations than the M1 5w30. However, boutique oils also likely have a lot to offer for concerned drivers (Redline, Amsoil) depending on how serious you are about base stocks and "true" synthetics versus highly refined blends like Mobil 1 5w30; combined with additives packages including zinc and phosphorous levels.

Using the premium oils also can extend your change intervals in the right street-car situation.

However, as a general rule - if you just drive your car on the street and "get on it" every once in a while at a stoplight or something, Mobil 1 5w30 is more than adequate. The M1 5w30 "extended mileage" also has a more robust additive package if I recall... but again this is splitting hairs for the average driver.

 

From 94-97, the API SH spec allowed up to 1200 ppm phosphorus for 5w30 and 10w30 and didn't address other 30 grade viscosity like 0w30. In 97, API SJ dropped the limit to 1000 ppm, but still did not address 0w30. In 01, API SL kept 1000 ppm phosphorus, but added 0w30 to the spec. In 04, API SM further dropped the limit to 800 ppm, but for the first time set a floor at 600 ppm and advertised that oil's were better. Essentially they were capping how much phosphorus the better oils could have and mandating the lowest amount the cheapest oils must have. The current API SN spec still has the band 600-800 ppm phosphorus.

Unfortunately, phosphorus, along with zinc, in a compound called ZDDP, or or zinc dialkyl dithio phosphate, forms an oil's primary anti-wear additive. The reason behind this is that phosphorus slowly poisons the cats and prevent the catalytic exchange that allows them to function properly. To ensure auto companies could meet the EPA's 100k+ emissions requirements, the API has slowly been dropping the limit on phosphorus.

So, any oil labeled to meet the current API SN spec will be limited to 800 ppm max phosphorus. This impacts how well it will be able to perform in anti-wear, such as might be seen in your bearings under heavy load.

There are aftermarket oils such as this that purposely don't meet the current API SN spec:
AMSOIL Z-ROD 10w30 Synthetic Motor Oil (Product Code ZRTQT)
(zinc – 1440 ppm, phosphorus 1320 ppm)

Note that an oil like this doesn't meet the owner's manual requirements which specify GM's new dexos1 spec (also 800 ppm phosphorus max).

Whether you need extra ZDDP for a street driven car is a matter for debate. At the track, I personally feel you do. I use this at the track in my stock LS6:
AMSOIL Dominator Synthetic 10w30 Racing Motor Oil (Product Code RD30QT)
(zinc – 1575 ppm, phosphorus 1474 ppm)

Finally, note that all of AMSOIL's current spec API SN oils do comply with the API 800 ppm limit thus do not have extra zinc or phosphorus. These are AMSOIL's oils that are labeled to meet dexos1 specs (thus no extra ZDDP):
AMSOIL Signature Series 100% Synthetic 5w30 (Product Code ASLQT)
AMSOIL XL Synthetic 5w30 (Product Code XLFQT)
AMSOIL OE Synthetic 5w30 (Product Code OEFQT)